National Rivers Authority - Anglian Region
Regional Flood Defence Committee Technical Visit to Bremen 22 - 24 May 1995
I Natl rs Authority II fiO .,.; rre
No .. l ^ ^ t o n No ..A .R .n ^ l Acknowledgments
The Anglian Regional Flood Defence Committee acknowledges and thanks Dr Hans Kunz and colleagues for the hospitality, friendship and technical excellence of the visit to Upper Saxony in May 1995. Contents
Page Number
1. Attendees 1
2. Itinerary 2 - 3
3. Introduction and report 4 - 11
4. Contacts in Germany 12 - 13
5. Photographs 14
6. Maps 15
7. Support Documents 16 ATTENDEES
Mr J S Martin RFDC Chairman Mr J M Childs Chairman - Great Ouse Local Flood Defence Committee Sir E Greenwood Vice Chairman - Norfolk & Suffolk Local Flood Defence Committee Mr D J Riddington Chairman - Welland & Nene Local Flood Defence Committee Ms F J Madgwick Member of Regional Flood Defence Committee - Broads Authority Mr W H R Squier Chairman - Essex Local Flood Defence Committee Mr C J Groome Chairman - Regional Rivers Advisory Committee and a member of the Regional Flood Defence Committee Mr R Payne Member of Great Ouse Local Flood Defence Committee and of Bedfordshire County Council Mrs B M Goble Member of Great Ouse Local Flood Defence Committee and of Hertfordshire County Council Mr D J Fisher Vice Chairman - Essex Local Flood Defence Committee Mr T E Dale Member of Essex Local Flood Defence Committee and of Essex County Council Mr R J Epton Chairman - Lincolnshire Local Flood Defence Committee
Mr R Runcie Regional Flood Defence Manager Mr A Baxendale Area Flood Defence Manager (Northern) Mr I W Hart Area Flood Defence Manager (Central) Mr J Hesp Area Flood Defence Manager (Eastern) Mr M Child Regional Manager Special Projects
1 REGIONAL FLOOD DEFENCE COMMITTEE
TECHNICAL VISIT TO BREMEN 22/24 MAY 1995
ITINERARY
Monday 22 May:
5.00pm (BST) Leave Stanstead 7.30pm (local time) Arrive Bremen
Transfer to Ubersee Hotel, informal dinner followed by sightseeing walk around centre of Bremen (time permitting).
Tuesday 23 May:
8.45am/9.00am Depart from hotel by bus to Department of flood protection/Sena fur Umweltschutz und Stadtentwischlung, Hansestadt, Bremen.
9.00am - 10.30am The flood protection of the Bremen area; demonstration of the storm flood forecast system (Head of the Department and his staff).
10.30am - 12.00pm By bus from Bremen to Elsfleth (Hunte Gate) with some stops for explanations.
12.00pm - 1.30pm Technical visit of the Hunte Gate (Storm Surge Barrier) and lunch. Presentations on the flood protection of the Lower Weser Estuary and its tributaries (especially Hunte with Oldenburg town) by the STAWA, Brake - Head and his staff.
1.30pm - 2.30pm From Elsfleth to Brake with stops in Brake village (flood protection constructions).
2.30pm - 4.30pm Lectures, tea and cake in the STAWA, Brake (Head and staf f^-
Orgamsation of the flood protection in Lower Saxony/Germany.
Protection of the low lying marshes along the North Sea against water (storm flood, fresh water runn off)-
Dike and Water Boards.
4.30pm - 6.00pm From Brake to Varel with stops on the Jade Bay (natural resort, pumping station, tide gate).
2 6.00pm - 7.30pm Hotel Friesenhof in Varel, relaxing or casual walk around town.
7.30pm onwards Informal dinner with representatives of STAWA Brake, Dike Board and Contractors; with lectures and discussions concerning development of the coastal protection for Germany and actual problems, such as integrated concepts, managed retreat etc. (Lead by our host, Dr Hans Kunz, Director of the Lower Saxonian Central Board for Ecology).
Wednesday 24 May
9.00am - 10.30am Reinforcement of the sea dike in Groden/Jade Bay:-
Technical solution
Problems concerning clay and sand reclamation for the construction
10.30am - 12.00pm Dangast, Petershorne, Wilhelmshaven (by bus with stops), for the "Sudstrand”, part of Wilhelsmhaven town. With representatives of: Contractors for sea dike, CRS, Nordcrney/Dep. Wilhelmshaven: Dike Board.).
12.00pm - 00.30pm Walk to the office of the National Parc Agency for Lower Saxony (by bus if weather is bad).
00.30pm - 4.00pm National Parc Authority Trilateral Wadden Sea Group Public Information Centre - lectures and discussions combined with lunch break. Various aspects of flood defence work to be covered depending on availability of time.
4.00pm - 7.15pm Head back to Bremen Airport.
7.15pm - 8.00pm There should be an opportunity to get a snack and tea/coffee at airport prior to departure.
8.00pm Leave Bremen «*-
8.15pm (BST) Arrive Stanstead
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In particular, strong links had been established with Dr Hans Kunz of the German Coastal Research Station based at Nordeney in Germany. Dr Kunz in liaison with Robert Runcie, Regional Flood Defence Manager, extended an offer to organise a visit of representatives from the Anglian Region Flood Defence Committee to Germany to see coastal protection works, to explore the ways in which our countries deal with common coastal protection problems and build technical links. The visiting party was led by John Martin, the Regional Flood Defence Committee Chairman, and included the Chairman and/or representatives from each of the Local Flood Defence Committees as well as the Regional and Area Flood Defence Managers. The visit began on the evening of the 22 of May 1995 and a full itinerary of visits and discussions took place over the next two days. The presenters included a number of those responsible for land drainage, flood defence and environmental protection in the areas visited. t BACKGROUND TO THE AREA The general area visited was around Bremen in the state of Lower Saxony in Northern Germany. The area has much in common with East Anglia having a coastline which includes both areas subject to wave attack and protected areas at risk from high tide levels, behind which He extensive low lying agricultural areas and navigable tidal rivers extending some distance inland to urban and industrial centres. Lower Saxony has a coastal area of around 8000 km2 and flood defence works including 1100 km of sea, channel and river embankments, 12 storm surge barriers and extensive defence works in the form of embankments as well as beach and dune protection works on the offshore east Friesian Islands. 4 The planning and development of flood defence works on the mainland is undertaken by Regional Agencies for Water and Waste Management, with Regional Government being responsible for considering feasibility and economic factors in conjunction with the Lower Saxony Minister for the Environment. At local level Dike Associations are responsible for the maintenance of the dikes and works to replace them where necessary. The Dike Acts which prescribe the duties and responsibilities of the various organisations were established principally following major flooding in the state in 1962 and these Acts prescribe the design standard of the defences which must be maintained. This has a profound effect on the promotion of flood defence works when compared with the situation in England and Wales. 5 DAY 1 - 23 MAY 1995 FLOOD CONTROL AND WARNING - BREMEN AREA The first visit was to meet staff of the local authority for environmental protection and town development in Bremen (which has State status). Hugo Wohlleben our presenter is responsible for flood warning and protection for the area around Bremen and Bremenhaven, and he outlined to the group the general warning and. protection systems in place and demonstrated some of the systems used for monitoring and forecasting storm surges. The area has some 170/km of flood embankments along the River Weser and its tributaries (the Lesum, Ochtum and Geeste). Following flooding in Holland in 1953 and in Lower Saxony in 1963 the tidal embankments were improved to design standards up to 1:1000 and 3 tidal barriers were constructed. Funding for these works were met from Federal (70%) and State (30%) sources. Modelling work to aid barrier design predicted that water levels downstream of the barriers would be increased by 0.7m and improvements in embankments were completed prior to barrier commissioning. The design standard and requirements of flood defence schemes are set in the Dike Acts and as such no cost benefit analysis is needed or carried out in support of capital schemes. The mean discharge for the River Weser is 300 cumecs (flood flows around 4200 cumecs) and the barriers close in a set sequence for water levels over 1.0m above mean high water levels. The Weser is navigable and navigation is an important influence on river management and barrier closure strategies. In 1994 the barriers were closed 113 times and it is estimated that without closure 80% of these level events would have caused some flooding. Flood warning and forecasting is done locally for the Bremen area by Mr Wohlleben’s team and is based on forecasting models which operate automatically based on telemetry data. Individual warnings are passed by telephone to industrial areas and public warnings are passed to the local ’emergency planning’ department who decide whether to issue warnings via local radio and loud hailers. If flood damage occurs without a warning being issued financial compensation is paid and is funded from local taxes. DIKE REINFORCEMENT SCHEME - MOTZEN The group visited the site of flood defence construction works at a disused industrial site adjacent to the River Weser downstream of the tidal barriers. The Dike Board are constructing a sheet piled tidal defence. Jurgen Kathmann of the Agency for Water arid Waste Management at Brake described the works to the group. At the time of bank raising prior to barrier commissioning the ownership of the defences was returned to local landowners/industries. No structured system of responsibility for maintenance and replacement was established and a large, number of individually negotiated arrangements were developed. 6 Whilst the Dike Boards do have compulsory purchase powers these have never been used. Where the Dike Board wishes to do works, as at Motzen, they must first buy the land on which the defence stands by negotiation. Works are therefore carried out on an opportunistic basis. The area has a number of flood gates across access etc. and the responsibility for closing these in flood events may lie with the Board, the factory owner or an individual householder. In practice the closure arrangements work very well (notified by telephone call when closure necessary). HUNTE STORM SURGE BARRIER The group were introduced at the site to Diethard Ness who is Director of the Agency for Water and Waste Management at Brake, Jan Renken, Chairman of 2nd Oldenburg Dike Board, and Mr Buschan, manager of the local Dike Board, and to the operators of the barrier including Mr Davis, a Scotsman who was passing through the area, liked it, and settled there many years ago! After a lunch the group were given a guided tour of the barrier by Mr Ness and his team. Following urban flooding from the storm surge of 1962, options to improve defences included extending the polder system or the construction of a single or multiple barriers. Poor ground conditions mitigated against polder extension and a single barrier was discounted for technical reasons. The preferred 3 barrier system (at Hunte, Ochtum and Lesum) was completed in 1979. The Hunte barrier consists of two flood openings with a clearance of 20m and two navigation openings with a clearance of 26m. Each flood opening and navigation opening has two hydraulically operated gates. The provision of two gates in each opening is for security in case of damage. The Hunte gate is closed if a water level of 1.0m above high water is forecast. The 3 barrier system, constructed at a cost of 342 million DM (approximately £153 m), has successfully protected the area from flooding. The works were funded 70% by Federal Government, 20% by Lower Saxony State and 10% by Bremen State. Operation and maintenance costs are borne by the States. A formal operating agreement between the two States was necessary for the scheme. WATER AND WASTE MANAGEMENT AGENCY - BRAKE Mr Ness and two of his team, Mr Jiirgen Kathmann and Mr Matthias Popkes, along with local Dike Board managers , gave the group further details of the organisation and management of flood defence and other aspects of water management in the area. 7 The Agency has 5 departments concerned with water resource management, water quality management (including waste management), flood defence, water protection and data and administration support. The Agencies with coastal areas have responsibility for both fluvial and coastal flood protection. Below this management tier lie the Dike Boards of which there are 27 in Lower Saxony. In the local area there are the Oldenberg 1 st, 2nd and 3rd Boards. The Boards own the Dikes and are legally responsible for maintenance and capital works. The Agency maintain an overseeing role of planning and development. The Agency’s consent is required for work within 50m of the defences. A charge is made for consent. The majority of the maintenance work is contracted out to local contractors by the Boards at an annual cost of 30m DM (approximately £ 13.5m). In addition to the Dike Boards there are Drainage Associations. The Dike Boards operate through a Steering Committee which is elected by landowners every 5 years with voting power based on land value. Local land drainage charges of around £20 - £100 pa are levied for small companies/houses and around £6 per hectare for agricultural land. The majority of the dikes are built on poor ground which is constantly settling at a rate of around lm every 30 years. The maintenance/rebuilding programme is therefore ongoing. To date only 30% of the coastal dikes meet the statutory standard. There are standard designs for ’river dikes* and ’coastal dikes’. Earthen dikes are preferred at all locations due to their low cost although due to the dimensions of the standard design, other designs (concrete walls, piled defences) are necessary in confined areas. JADE BAY NATIONAL PARK The Jade Bay is a large tidal embayment on the coast. It is a National Park and an important conservation area. On its western side lies Wilhelmshaven which is a deep water port. The Bay has extensive saltmarsh areas and local conditions have led to development of what is called a ’floating moor’. The perimeter defence of the bay is principally and earthen dike defence with a sheet pile crest defence in restricted places. The shape of the bay has changed constantly over the last 800 years and shifts in eroding and depositional areas continue today. There are ongoing programmes of dike reconstruction around the Bay to meet the design standard. The Bay has historically been a source of clay and sand material for dike construction and this is currently a source of concern between engineers and conservationists over protection of both the flood defence and conservation assets. As at other sites the sea dikes are large structures, with access roads on both seaward and landward sides. At Jade Bay the grass is controlled by sheep flocks which are financially subsidised for the purpose. The Group were informed by Mr Renken that further detailed consideration of the management issues of Jade Bay would be provided on day two. 8 JADE WAPEL DRAINAGE SLUICE The group were introduced to the site by the Dike Board Chairman, Mr Gerd Haschen and the Pumping Station Superintendent Mr Ehmen. The pumping station lies on the landward side of the sea dike. It drains 24000 hectares and has around 1000km of watercourse. The 4 vertical impeller pumps can discharge up to 34 cumecs into the tidal Jade Bay. Within the drainage area 300 km of watercourse are maintained by the Board and the remainder by riparian owners. The design of the drainage arrangement is such that 85% of the time the old gravity sluice station is used and the pumping station is used only for 15% of drainage water. The outfall channel into Jade Bay is 10km long and annually 200,000 m3 of silt is ’removed’ from this channel by agitating the silt and letting the tidal current flush the sediment - which of course returns and the process is ongoing. Land drainage charges are around £6 per hectare. 9 DAY TWO - 24 MAY 1995 DANGAST AND CACILIENGRODEN SEA DIKE REINFORCEMENT SCHEME - JADE BAY At Caciliengroden on the edge of Jade Bay the group were shown the ongoing dike reconstruction works. The works were presented by the Gerhard WeiB, Chief Engineer (Dike Board) and the Contractor to the works. At Dangast the defence consists principally of an earthen sea dike but there are other areas of natural sand moraine defence with ancillary retaining walls. A gravity sluice drains a large storage basin behind the defence which uses an upstream pumping station to store up to 3 times tide lock water volumes. Only low lift pumps and associated energy costs are required because high tide levels do not have to be overcome. The whole of this area around Jade Bay is founded on poor ground and subsidence is constantly occurring. This has required a dike reconstruction scheme which the group viewed at Caciliengroden. Because the standard and design of defence required is defined by statute the engineers have to consider what materials to use and where to obtain them from, given the prevailing conservation considerations. Borrow Pits for clay and sand (sand is used for the dike core because insufficient clay is available) are obtained from both the bay (seaward) and landward sides. In promoting such proposals the engineers, in conjunction with environmentalists, define available material source options, along with the environmental implications and submit them to the State Minister for the Environment who gives direction on what options to adopt. This process is normally concluded within 2 years of option identification. Work on the sea dikes is only permitted during the summer months (May - September). Whilst there is no cost-benefit assessment required for the work, money is allocated to the schemes on an annual basis and this tends to prolong construction times. For the 9.5 km reconstruction scheme at Dangast the cost will be 70m DM (approximately £31 m) and will take 7 years to complete (annual financial limitations). Historic borrow pit development in the Bay has initially created new habitats but after 10-30 years initial conditions are restored. The conservationists advise the engineers on the areas where borrow pits will cause least environmental damage. There has been substantial saltmarsh development works in the bay using artificial channels to encourage waterflow and siltation. Brushwood groynes are then used to encourage saltmarsh development. Additional environmental opportunities/enhancements are provided for these dike reinforcement schemes by developing new wetland conservation areas from any borrow pits used on the landward side and in addition land close to the defence is taken out of agricultural production to compensate for the disturbance effects of the works. 10 At Caciliengroden 30 hectares is being taken out of production (note use is agricultural -dairy) for 6 years. WILHELMSHAVEN The group were taken on an informal, but informed visit to inspect the Wilhelmshaven tidal defences by Ommo Tjardes. The careful landscaping of the defences of the defences to blend in with this attractive harbour town were a major feature. NATIONAL PARK AGENCY FOR LOWER SAXONY The group had several presentations from Reinhard Zander (Vice Director), Dr Hubert Farke and Klaus Wonneberger of the National Park Agency. Volkert de Jonge of the Trilateral Working Group on Conservation in the Waddensea widened the discussion to cover the Southern North Sea. The Acts setting up the Park require the Agency to protect natural systems - so the Agency is seeking so far as possible to eliminate human interference (no maximised bio-diversity). The Agency start work with the engineers at an early stage on identification of opportunities to minimise the impacts from the dike reinforcement schemes. However, the conservationists accept the vital importance of the flood defence work and in any event the flood defence requirements are embodied in the Dike Acts. The Agency work within the Dike Boards to identify options for minimising environmental impact. These are then forwarded with supporting information to the Environment Minister for direction on which option is to be delivered and funded. The Agency team gave additional presentations on the potential ecological impacts of borrow pits on saltmarshes, on public access to the Park and on the Trilateral Working Group on conservation in the Wadden Sea (Germany, Denmark and Netherlands). REVIEW The technical visit was an excellent opportunity to view how our German colleagues deal with coastal flood defence and maintenance issues and to draw parallels and variances with the UK situation. John Martin thanked all those who had played a part in a most successful visit and gave thanks especially to Hans Kunz for the excellent itinerary and very warm German hospitality. Opportunities were discussed for the Anglian Region to host a return visit for Dr Kunz and his colleagues at some time in the future. 11 Andy Baxendale June 1995 Area Flood Defence Manager CONTACTS IN GERMANY 1. Staatliches Amt fur Wasser u Abfall (StAWA) HeinestraBe 1 26919 Brake - Diethard Ness (Director) - Matthias Popkes - Jurgen Kathmann - Mr Buschan (Hunte Gate) - Ommo Tjardes (guide in Wilhelmshaven area) 2. Senator fur Umweltschutz u Stadtentwicklung, Abt. 6 Wasserwirtschaft Hansestadt Bremen Theodor - Heuss - Allee 21 28215 Bremen - Hugo Wohllenben (Director) 3. Wasser-und Bodendenverbande im Landkreis Wesermarsch Franz-Schubert Str 31 26919 Brake a) Jan Renken, * Vorsteher des 11 Oldenburgishcen Deichbandes b) Gerd Haschen, * Vorsteher des Entwasserungsverbandes Jade - Mr Ehmen (Jade Pumping Station) please write a) ...in Wasser und ... b) ...in Wasser und ... 4. Wasser und Bodenverbande, III Oldenburgischer Deichband Anton Gunther Str 22 26441 Jever - Hans Neinrich Schriewers (Vice-Chairman of the Dike Board) - Mr Bartels (Head of Staff) 5. Arbeitsgemeinschaft "Caciliengrodendeich" Flutstr 92 26388 Wilhelmshaven - Gerhard WeiB (Chief Engineer) - Jurgen Quadfasel 12 * "Vorsteher" is "Chairman" -2- 6. Nationalparkverwaltung Niedersachsisches Wattenmeer Virchowstr 1 26382 Wilhelmshaven - Reinhard Zander (Vice Director) - Hubert Farke, Dr. - Klaus Wonneberger 7. Trilaterales Wattenmeersekretariat Virchowstr 1 26382 Wilhelmshaven - Volkert de Jonge \ 13 PHOTOGRAPHS 1. Mr Wohlleben outlining the flood defence system for Bremen. 2. Sheet piled tidal defence protecting properties at Motzen. 3. Sheet piled defence adjacent to tidal River Weser at Motzen. 4. Mr Kathman outlining the Motzen scheme to the group. 5. Hunte Tidal Barrier. 6. Hunte Tidal Barrier - one of the pairs of navigation and flood discharge gates. I. Group enjoying lunch at-the Hunte Barrier. 8. The National Park of Jade Bay, Nr Varel, (sheet pile defence in foreground). 9. The sea dike (landward side) with sheet piled crest and grazing sheep at Varel. 10. Group at Jade Bay, Nr Varel. II. Outfall into Jade Bay from pumping station at Wapel. 12. Storage basin upstream of drainage sluice at Dangast. 13. John Martin and Hans Kunz (second right) at the Caciiiengroden scheme site office. 14. Group inspecting dike reconstruction progress at Caciliengroden. 15. A section of reconstructed dike (looking seaward) at Caciliengroden. 16. Group Photograph 14 2. Sheet piled tidal defence protecting properties at Motzen Mr Jurgen Kathmann outlining the Motzen scheme to the group 6. Hunte Tidal Barrier - one of the pairs of navigation and flood discharge gates 7. Group enjoying lunch at the Hunte Barrier 8. The National Park of Jade Bay, Nr Varel (sheet pile defence in foreground) The sea dike (landward side) with sheet piled crest and grazing sheep at Varel Group at Jade Bay, Nr Varel 12. Storage basin upstream of drainage sluice at Dangast 13. John Martin and Hans Kunz (second right) at the Caciliengroden scheme site office 14. Group inspecting dike reconstruction progress at Caciliengroden 16. Regional Flood Defence Committee and German Colleagues Bremen - 22/24 May 1995 MAPS 15 General Area of the Technical Visit 3 10 15 20 28 Km The Hunte Storm Surge Barrier Ansicht von oberstrom 1 2 SUPPORT DOCUMENTS 1. General information on the Lower Saxony area and Water Management administration. 2. Flood warning and control in Bremen - details. 3. Typical defence cross-section at Motzen. 4. Hunte Tidal Barrier - background details. 5. Jade Bay - typical sea dike cross sections. 6. Caciliengroden - typical reconstructed dike cross section. 7. Jade Bay National Park - Conservation details. 8. Wadden Sea - trilateral areas of conservation. 16 S M T O ffm GWilR AUTIHOiRDTY - AM©yAINI IRi©0@lim M © ® IW i^Cl €©MTFTIi TiCMCM mQT m - M sw m§ (gjljftHiRM, IMTA 1 Government and Administration in Lower Saxony: State of Lower Saxony Government of Lower Saxony Minister of Environmental Protection 4 Administrative Regions (Provinces) 39 Rural Districts (Counties) 9 City Districts (Municipalities) 7 Independent Greater Cities 1 Special Status City 409 Community Districts 2 Water and Waste Management Administration in Lower Saxony: 2.1 Affairs of Water Management and Protection, Waste Management, Coastal Protection; Federal and State Water Management and Protection Acts; Federal and State Waste Management Acts; Lower Saxony Dike Act; 2.2 Supreme Authority - Minister of Environmental Protection; Superior Authorities - Governments of the Administrative Regions; Inferior Authorities - Rural and City Districts; State Agency for Environmental Affairs with ist Department for Coastal Research; 11 Regional Agencies for Water and Waste Management; 1 Agency for Island and Coast Protection; 3 The Regional Agency for Water and Waste Management in Brake (StAWA Brake) 3.1 The Region: Area 3488 km2, Population ~725.000 inhabitants, Density of population -208 l/km2, Land use: Agriculture, Horticulture 67%, Forestry 5%, Waters 3%, Traffic 6%, Other use 19%, Land elevation -2,0 m NN to +55,0 m NN 3.2 The Administration: StAWA Brake lies Within the Administrative Region of Weser-Ems with its government seat in Oldenburg. The region of the StAWA Brake consists of 4 rural districts (Ammerland, Friesland, Oldenburg, Wesermarsch), 3 city districts (Delmenhorst, Oldenburg - City, Wilhelmshaven), within them 31 communities. 3 local „Dike Associations" are legally responsible for all coast protection works, especially maintenance of the dikes. 3.3 More statistics of the StAWA Brake agency and its region: Staff of about 120 men and women, 5 departments with 14 subject offices, 1 hydrochemical laboratory, Length of designated main dikes 243 km Coastal area protected by dikes and storm surge barriers 1.743 km2 River Weser - Estuary -55 km River Weser - Tidal River -70 km Tidal section of the river Hunte -25 km River Hunte (above tidal influence) -60 km Waters of secondary order 3.600 km Tidal gates and pumping stations in the coastal main dikes (drainage sluices) 28 structures Lowland pumping stations 128 Popkes, StAWA Brake, May 19,1995 The Coastal Protection Administration of Lower Saxony, Federal Republic of Germany The protection from storm surges of the Lower Saxony coastal area of about 8000 km2, its population and property is achieved by about 1.100 km sea, channel and river embankments, 12 storm surge barriers, extensive defense works in front of embankments and a system of approach roads for embankment maintenance and cases of emergency. In addition to this there are beach and dune protection works on the East Friesian Islands. The aim of the „Lower Saxony Coastal Programme" is to build these coastal works in line with latest knowledge. The most recent expression of this programme is still the 1973 „General Plan for Coast Protection in Lower Saxony“ laying down standards for further coast protection. An updated and slightly modified version is presently in process of completion. The „Lower Saxony Dyke Act" (Niedersachsisches Deichgesetz) lays down that the landlords of all plots of land situated within a potential flood plain and sheltered by embankments or a storm surge barrier are jointly responsible for the maintenance of the embankments. Some 27 local Dyke Associations (Deichverbande) have been founded to carry out this task . They own most of the embankments and as far as their property is concerned they act as applicants for new schemes and rehabilitation projects. The maintenance of an embankment includes establishing or re-establishing the prescribed dimensions of such embankment and related works. On the other hand the Dyke Act assigns certain tasks to the State of Lower Saxony itself. These include the building, operation and maintenance of all storm surge barriers and coastal protection measures on the East Friesian Islands. In addition to this the State of Lower Saxony bears the whole cost for carrying out reconnaissance surveys. For this reason, the „Regional Agencies for Water and Waste Management** (Staatliche Amter fur Wasser und Abfall) which locally represent the Lower Saxony State Administration have taken over most of the planning and development of coast protection measures on the mainland. Prooving the feasibility and economicy of coastal protection schemes is the task of the Regional Government Weser-Ems and the Regional Government Luueburg respectively (BczirUsrcgicrang Weser- Ems, Liineburg) which also officiate as supervising authorities i.e. ^Superior Dyke Authorities" (Obere Deichbehorden) to the Embankment Associations. The Lower Saxony Minister for Environment, the highest level Dyke Authority, has retained the privilege to agree to or to veto plans. „Rural District Authorities" (Landkreise) and Municipalities of concerned areas represent the ,inferior Dyke Authorities" (Untere Deichbehdrden) which are mainly in charge of organising emergency defense measures and regular technical inspection of the entire line of embankments, drainage sluices and storm surge barriers. The latter is usually done in close cooperation with the Regional Agency for Water and Waste Management. The , .Government Agency for Island and Coast Protection“ in Norden (Staatliches Amt fur Insel- und Kustenschutz) signs responsible for various special tasks like land reclamation and coastline conservation schemes as well as all coast protection measures on the East Friesian Islands. The „Coastal Research Department" (Forschungsstelle Kiiste) on the island of Nordemey is involved in a broad scale of scientific research projects which among others includes basic research to be taken into consideration for coast protection policies. revised and updated from „Coastal Engineering System Organisation and Administration" , compiled by Josef Sindem in „Die Kuste" Archive for Research and Technology on the North Sea and Baltic Coast, Heft 32,1978, published by Kuratorium fur Forschung im Kusteningenieurwesen (German Committee for Coastal Engineering Research), Kiel, FRG Bremen, 15.05.1995 Wo/Te Floodprotection for the Bremen area (Visiting of British engineers 23. May 1995) Ladies and gentlemen - I welcome you in Bremen! I am glad that you are visiting the authority for environment protection and town development of the Free Hanse-Town Bremen; this smallest country of the Federal Republic of Germany consists of the two towns Bremen and Bremerhaven placed at the River Weser. These together haafabout 685 thousands inhabitants. One of the essential things is to protect Bremen and Bremerhaven against storm-gale floods. Therefore exists 170 km dikes along the River Weser and the affluents Lesum, Ochtum and Geeste. 4 river-barriers are shortening the main line of the dikes: in Bremerhaven the Geestesperrwerk, in Lower Saxony the Huntesperrwerk and Ochtumsperrwerk and in Bremen the Lesumsperrwerk. In the earlier days the tidal range of the River Weser was not as high as today. About 1887 the regular tidal rise in Bremen-town was nearly half a meter. With the systematic development of the watercourse of the River Weser between Bremerhaven and Bremen beginning 1887 the mean tidal range increased to 4 meters, during the highest high-tides to 9 meters. After the „Holland - Storm-gale-flood“ 1953 the whole coastal protection plan was overhauled. New heights for the dikeconstructions was laid down as rules. Bremen developed new dikeconstructions at once. At the same time the Federal Government, Lower Saxony and Bremen commisioned the Franzius-Institut at the University of Hannover to find out by model tests which waterlevels are possible by different conditions for storm-gale- floods and run-offs from the Weser-catchment area. Also they should find out which effects constructions as harbour-plants, developing the navigable water or barriers to the affluents can have. These model tests give the following results: 1. The highest expected high-tide watermarks were calculated. 2. The safest and most useful protection of the areas along the rivers Lesum, Wumme, Ochtum and Hunte is obtained by barriers to the three affluents Lesum, Ochtum and Hunte. 3. The closing of the barriers raise the high-tide water-levels of the Weser in frontK)- of the barriers. 4. Significant is only the construction of all three barriers. The storm-gale-flood 16. and 17. February 1962 brought new unknown water-marks. The mark for Bremen Vegesack was +5,22 m NN (over mean sea level). That was 1 meter higher than ever before. The dimensioning watermark for the year 2100 had been ascertained again and again new heights for the dikeconstructions was laid down as rules. The new height foi{2100 is grounded on the following points: 1. The project to construct 3 barriers for Lesum, Ochtum and Hunte means that the water marks for the gauge Vegesack would increase until to 68 cm. 2. It was supposed that even more unfavourable storm-gale situations could come as there were in the high tide night 16. to 17. February 1962. Additional there could be a higher Weser-run-off as the then being high-tide. 3. The so called secular rising of the sea level, that means the common rising of the North sea-level, was calculated for the period of 100 years with 20 cm. 4. Developing measures decreasing the waterlevel for instance harbourplants- developing has been regarded to the water mark 2100. Round about 69 km dikes was built up higher until 1972, - the barrier Lesumsperrwerk was 1974, - the barrier Ochtumsperrwerk 1976 and - the barrier Huntespemverk 1979 ready for working. Together they were set running in November 1979. Since 1955 nearly 300.000.000,- DM were spent for the flood- protection developing in Bremen and Bremerhaven. The annexed picture shows the crown-water-levels of the tenth highest storm-gale- floods registered from 1900 until today for the water level gauges along the River Weser between Bremen and Bremerhaven and for the German bight. One of the main points out of the management on flood protection is the high tide forecasting. (see also the corresponding text with date 15.05.1995) Annex: 1 cetlasrtne e 1 hcse, n ism arudr a Pegel am Jahrhundert diesem in hochsten, 10 der Scheitelwasserstande Wasserstand [NN + Bucht. Deutschen und Unterweser der Pegeln den an Wasserstande eeak ugteee Sumltn n i entsprechenden die und Sturmfluten aufgetretenen Vegesack okm leWsr rv Bae eeak .K Weser W.-K. Vegesack Brake Brhv. Weser Alte Borkum Pegel rce Wehr Brucke -Stand 09.11.1994- -Stand H. Wohlleben Bremen, 15.05.1995 d o Senator for Environment-Protection Wo/Te and Town-Development Short Version of: High tide forecasting for the town of Bremen In the year of 1979 three river-barriers were set running in the area of the River-Weser between Bremen and Bremerhaven. These barriers makes it possible to held definite waterlevels in the affluents Lesum, Ochtum and Hunte (Picture „Abb. 2“). (The three barriers are: „Lesumsperrwerk, Ochtumsperrwerk and Huntesperrwerk“.) The table „Tabelle 1“ on page 3 shows the numbers of the closings of the ,rLesumsperrwerk“ from the year 1980 to the year 1994. The definite closing-water-level to protect the dikes along the River-Lesum and River-Wiimme is +2,70 m NN (above the mean sea level). For instance in 1994 the „Lesumsperrwerk“ was closed 113-times. To forecast the right moment in relation to the definite water-level of 2,70 m NN is very important on one hand. On the other hand there are additional steps of water-levels to start the high-water-protection organisation because of gale-warning. In the first years all the time the persons concerned have to forecast by own hand on day and night; therefore they have to go to the official bureau. We develloped a forecast-system based on computer ringing up the persons concerned. So we can avoid frequent walking to the official bureau. Using the water-level-gauge ,JBorkum“ and „Alte Weser" the computer works out the forecast for the water-level-gauge „Vegesack“ and „Lesumspemverk“. (Picture „Abb. 2“). Table „Tabelle 3“ on page 9 shows you an example of a forecast-occurence for the night-high-tide belonging to the gauge „Vegesack“. Eleven minutes past two in the morning the high-tide should reach „Vegesack“ on 16. March 1995. The first high-water-level-forecast („1. Hochwasservorhersage") is plotted at three minutes to nine o’clock in the evening 15. March 1995 („15.3.95, 20.57“). That is about 5 hours before the astronomical time for „Vegesack‘\ The computer ist calculating on two improvements one and two hours later. The computer rings up the person concerned. This automatic system works since ten years without a servant. The computer uses five-minutes-median numbers of water-level-informations, which are coming on-line as analog informations. During the next year the on-line remote transmission will be change to a digital signal, what means a new hardware equipment for round about 400.000,— DM. In case of a gale-waming combined with a forecast more than +3,50 m NN (above mean sea level) it is possible to use additional water-level gauges along the River-Weser similar to the flood running in from „Borkum“ via „Alte Weser“, ,3remerhaven“, „Brake“, „Vegesack“ to „GroBe Weserbrucke“. Gauge „Oslebshausen“ is a self anounce gauge and gives the actual water level. Hints to the tables and pictures: Table „Tab. 1“ Page 3: Management of the Lesumsperrwerk (River-barrier for the River-Lesum) - number and frequency of closing the barrier. Table „Tab. 2“, Page 4: Temporal running of the tides for the example of the night-high-tide in Bremen from 15. to 16. March 1995. (The time difference between the water-level-gauges Borkum and Vegesack is 3 hours and 57 minutes.) Tabel „Tab 3“, Page 9: Example of high-tide-forecast for the night-high-tide gauge Vegesack from 15. to 16. March 1995. Picture „Abbl“: Hardware equipment and water-level recorder for the high-tide-forecasting-system. Picture „Abb2“ : Locality-map to the position of the water-level- gauges for the high-tide-forecasting-System in Bremen. ( The Hunte gate In 1953 the Netherlands were struck by an extrem high tide. One year later at Christmas a similar high water happened on the German coast. The water level reached nearly the crown of the dikes at that time. Both events caused the federal administration as well as the governments of the north German federal countries to check the security of their coastal dikes and other constructions on the sea. As a result of it in the fifties a big “coastal protecting programme" was started. Very soon it became clear, that most of the dikes were too low and the structures within not safe enough. So the dikes along the coast had to be made higher and get minor step side slopes. Along the tidal rivers Elbe, Weser and Ems it was more difficult to reinforce the dikes in the same way. A lot of buildings of any kind often gave not enough room for the needed measurements. This was even more true for the tributary rivers of the Elbe, Weser and Ems, because of the weak ground, which is not strong enough to carry the higher weight of a new and greater dike. So at the mouth of the tributary rivers gates were projected. Those gates are both the best flood control and the most economic plant. At the beginning of the project in 1954 hydraulic researches of the Weser river basin took place at the Technical University of Hannover. The purpose of these experiments was, to find out how large the opening of the gates must be, so that the normal tide can pass without any backwater. But the research also showed, that when the gates are closed, the level of high water in the Weser will increase. The reason for it is, the flood absorption effect of the reservoirs in the tributary valleys can no longer be filled. - 2 - In case of an extraordinary flood, as in 1962 and 1976, an increase of the flood peak from 0 cm in Bremerhaven up to 67 cm in Bremen must be expected. In 1968 the federal countries of Lower Saxony and Bremen contracted a joint project for the tributary rivers of the Weser, which are the Lesum and Ochtum near Bremen and the Hunte. The definite project plan was finished in 1969. To get the formal acceptance by the department concerned was hard work, because 955 objections to the project were registered. Most of the objections were caused by the increase of the flood peak and protecting measures were claimed. The formal acceptance was given on the 18.01.1971 and the work could start. The work began at the Lesum gate in 1971, the Ochtum gate followed in 1972. At last the construction of the Hunte gate started in 1976. On Oct. 1, 1979 the three gates and the flood protecting measures were finished. The Hunte gate was built on the north point of the Elsflether Sand, a small island at the mouth of the Hunte. As the building site was outside the dike, at first a cofferdam was built with crown on NN + 6,0 m to protect it against high v/ater. Inside the wall the foundation concrete had to be put in submerged, because groundwater draw down in the needed depth was not possible. A settlement of the week soil below the town auf Elsfleth would have brought the houses into danger of damage. The Hunte gate has got two flood openings with a clearance of 20 m and two navigation openings with a clearance of 26 m. Each flood opening has got two radial gates and the navigation openings two mitering gates. Two gates in each opening are necessary for further security in case of a damage. The gate has got a bridge too, maximum load 30 t. The parts of the bridge crossing the navigation openings are a rolling lift-bridge-construction. The gates and the lift-bridges have got an oil-hydraulic-drive. The running pressure is approximately 100 bar. In case of overload security valves leads the oil back into the oil-tanks. - 3 - The Hunte gate has to be closed, if a water level of 1,0 m or more than mean high water is expected. That happened at an average of 23 times in the last years. By this the areas outside the dike in Elsfleth have not been overflooded since then and the train connections from Hude to Nordenham have not been interrupted. The whole system is controlled and driven from the contro11-center on a tower. It is on work round the clock. A system of gauges, organised and watched by the watermanagement board of Bremen and Brake give the alarm to shut the gate in time. The construction costs of the three gates at the Weser including the protecting measures amounted to 341,7 Hill. DM including the Hunte gate with approximately 110 Mill. DM. The whole sum was raised with 70 % by the Federal Government, 20 % by Lower Saxony and 10 % by Bremen. The operation and maintenance charges are raised by Lower Saxony and Bremen. uesnqepor pun 6por uo noqifo/eg — Neues Deichprofit — Bin i ______L Introduction to the National Park ..Niedersachsisches Wattenmeer“ (NLP) The NLP in Lower Saxony was founded in 1986. The area is 2.400 square kilometres. Included are the tidal flats, the saltmarshes along the shore and the islands between the rivers of Ems and El be. The landside border is the main dike, the seaside border is fixed by the geographical line in the map. The purpose of the foundation of the NLP is to ensure a large coherent natural site with it's natural processes, vegetation and wildlife. The east frisian wadden sea is of great importance as - resting and moulting place in the migration of birds (east atlantic flyway) - nursery for North Sea fish The included ecosystems are: - tidal flats, which flooded and left dry again with the changing tides; 2 - saltmarshes and i dunes with it's special species of plants and animals. In the region of the wadden sea people live and work since some hundred of years. So the ecosystem is not real natural in the scientific sencg of „without any influ ence of human being". For example there are enforce ments of the islands on their eastern parts. So the trend of natural movement of the islands to the southeast is re duced. Other traditional activities in the NLP are fisheries, far ming or tourism. The east frisian coast is the most important region for the tourism in Lower Saxony. Because of the difference between the NLP-idea in the sence of IUCN and the reality of human utilisation the NLP-decree is a compromise. A system of zoning is set up. Zone I is the care zone of nature conservation. It covers the most sensitiv areas like nursery places of seals etc. 3 All human activities which are able to influence the ecosystem are forbidden. It is only allowed to enter Zone I on official streets, paths or routes. Zone III is the recreation zone. It includes the traditio nal beaches with function for recreation. The regulation of Zone II are a compromise of the other. The special purpose is here to ensure the character of the landscape. For example it is forbidden to make noise, * 1 : to destroy the vegetation, to construct buildings etc. Quiet recreation, agriculture, hunting are allowed. The shipping routes, harbours, airports and villages on the islands are not part of the NLP. \ In the following the special problems of keeping natural processes of succession in a very dynamic ecosystem in relation to the demands of the inhabitants were explained by dike enforcement, measures in the western Jadebu- sen. r' Natural values of the ecosystem The tidal flats and saltmarshes of the Jadebusen are very important resting, moulting and breeding areas. For ex ample: 500 breeding pairs of Redshank per year. 3600 moulting Avocets (30 % of all Avocets of the east atlantic fly way). 2700 Shellducks per month are resting. The saltmarshvegeiation is nearly natural (60 % are wether grazed or mowed). There are natural conditions for an increasing of the saltmarsh biotopes. Special problems of the dike enfor cement measure (worked out in a environmental impact study). conflicts: a) enforcement to the seaside lost of saltmarsh biotopes as consequence of the expandation of the dike basis ...... b) destruction of saltmarshes as consequence of the take off the clay for the dike construction 5 c) limited destruction of tidal flat biotopes as consequence of the take off the sand for the dike construction d) limited disturbances as consequence of the construction activities like movement and noise of people and machines. The value of the breeding and resting places birds is reduced. Objectives of landscape planing These problems have to be managed in the permission act of the administration in order of the Nature Conserva tion Law and the National Park Decree. The Objective is to avoid environmental impacts as far as . / possible. For all environmental impacts compensation measures have to be constructed. To avoid impacts, the NLP-administration prefers the dike extension to the inland side. Suggestions for compensation measures in the actual planing are: 6 - areas for the development of natural saltmarshes have been chosen. Grazing and mowing activities have to be stopped, - to ensure areas for the development of brackish bio topes and managing of medows as breeding areas for birds. * At least, all is a problem of the costs. The NLP-administration prefers a dike widening variant that costs 8.6 Mio. DM more than the cheapest technical variant. So it is the state's decision „How much money shall nature conservation costs?" Visit of the National Park Administration of Lower Saxony 24.05.95 information facilities in the Wadden Sea National Park of Lower Saxony In the national park of Lower Saxony in total 17 information facilities are planned, 15 of which have already been built up. Among these are 3 bigger "Nationatpark Zentren”, which have to offer environmental education programmes for schools and adults. At the begin ning the smaller "Nationalpark-Hauser" have had their emphasis in information work, but • environmental education today also takes place. "Nationalpark-Zentren" are situated in Norden/Norddeich, Cuxhavenand Wilhelmshaven. The Wilhelmshaven center will finally be opend in 1996 and will be the biggest one in the park. "Nationalpark-Hauser are already situated on 5 of the 7 inhabitated Eastfrisian Islands of Borkum, Juist, Nordemey, Baltaim and Wangerooge; Langeoog and Spiekeroog will follow within the next years. On the mainland "Nationalpark-Hauser" are located in touristic areas. All information facilities are run by local authorities, in most cases in cooperation with diffe rent NGO's. The government of Lower Saxony gives financial support to the local authori ties as well for building up and installing the facilitiy as for the working costs including staff. The amount depends on the type of facility and the local position in the park. Those facili ties which are situated on the islands get some more money as those on the mainland. The “Nationalpark-Zentren" get about 180.000 DM a year each, the "Nationalpark-Hduser” between 120.000 DM and 135.000 DM. The facilities are opend throughout the whole tou ristic season and during holidays in winter, the "Nationalpark-Zentren" are more or less opened the whole year. Ail facilities have an exhibition on the wadden sea. The contents of the exhibition is not standardized by the national park administration but each facility shows local aspects and problems of the wadden sea and the national park. The eider facilities by and by will be re designed with regard to a "corporate design" which is common for the whole Government of Lower Saxony now. Besides this the facilities offer the following programme in different emphasis: - Guided tours to dunes, salt marshes or tidal flats -Floristic or omithollogic excursions - Seminars of one or more days - Lectures, also in cooperation with local tourist offices Staff by financial support of the government Nationalpark-Zentren: 2 each Nationalpark-Hauser 1,5 each This staff is supported by volonteers of NGO's. Coastal Research Station (NLO - Forschungsstelle Kuste Nordemey) Ecological problems concerning dyke reinforcements with reference to the effects on saltmarshes and wadden sea in the National Park „Lower Saxonian Wadden Sea*1 At the coast of Lower Saxony mainly the increased requirements on coastal defense have caused the necessarity for raising and reinforcing large parts of the sea dykes. These building projects have di verse effects on the saltmarsh and wadden sea ecosystems, which particularly after foundation of the National Park .Lower Saxonian Wadden Sea" in 1985 cause some conflicts between coastal defense and protection of nature. The most important contentious issues are the removal of clay from the saltmarshes, the destruction of saltmarshes by building over and the removal of sand from the wad den sea. As only a few investigations were available to provide help for decisions with regard to this problems in the approval proceedings, more intensive research was necessary. Since 1989, the NLO - Forschungsstelle Kiiste (NLO - FSK) carries out research on these subjects; the backgrounds and aims of the investigations are explained below. Clay removal from the saltmarshes From the beginning of dyke building the necessary clay was usually taken from the saltmarshes out side the dykes because this was the cheapest solution and the - from an economic point of view - more valuable land inside the dykes was saved. In the recent years the aspect of nature conservation has come to the fore; therefore the question arose if in general a further removal of clay from the saltmarshes should be allowed in this ecologically valuable area which anyway is a part of the natio nal park. For finding an answer to this question, at first it was necessary to research the refilling and developing of former clay pits and to determine their ecological value within the saltmarsh ecosystem. For this purpose the NLO - FSK is investigating clay pits at the age of 2 to 40 years and - for comparison - saltmarshes with different agricultural treatment in the Jadebusen and Elisabeth-AuBengroden since 1990. The clay pits are examined for refilling with sediment (i. e. soil development and level), for recolonization with plants and evertebrate fauna and for acceptance by resting and breeding binds. The investigations have shown that a clay pit first - for a few years - is withdrawn from its function as a biosphere for plants and animals, but in the long term valuable saltmarshes can develop again. The different morphological structures between former clay pits with their natural developed mud flats and the man-made ditch structure of the old saltmarshes is obviously (fig. 1). Also the vegetation and its valuation in relation to the surrounding saltmarshes can differ a lot; in saltmarshes which are very rich in species and flowers, for example on the east side of the Jadebusen, a clay pit means a reduction of the vegetation because some species which depend on reaping don't recolonize a clay pit even within 30 years (fig. 2, 3). On the other hand, in areas with very monotonous saltmarshes clay removal in the long term rather may enrich such saltmarsh systems. The evertebrates and birds usually recolonize former clay pits rather fastly; in many older clay pits even relatively high abundances of quite a lot specialized saltmarsh inhabitants are found. A second field of worK within the saltmarsh research is the examination of selected saltmarsh areas with regard to their suitability for future clay removal. For this purpose the same parameters are in vestigated as described above. The valuation of these areas by ecological and nature conservation criterions shall provide a better basis for the proper authorities for further decisions whether and where clay is to be removed from the land outside the dykes. Destruction of saltmarshes by building over For raising a dyke its basis has to be widened out; mostly two building variants are possible, a wide ning inwards or outwards the dyke. In case of a widening outwards a strip of saltmarsh of 30 m width will be built over, and the saltmarsh in this strip will be destroyed permanently. In 1992, the ecological value of this strip of saltmarsh close to the dyke in relation to the areas folio- wing seawards was examined for large areas of the Jadebusen by the NLO - FSK. The results are used for the approval proceedings to determine the impacts of the dyke building on the environment. A criterion for the decision on which side the dyke is to widen must also be the ecological value of the relevant area inside the dyke. Sand removal from the wadden sea Since 1962, dykes are not any more built exclusively with clay but contain a heart of sand. The mate rial for this purpose usually was taken from the wadden sea where the pits get refilled with sediments and recolonized by benthic organisms within a few years. Research on the development of such areas is carried out by the NLO - FSK since several years. Also in the future the removal of sand from the Wadden Sea National Park can't be completely avoi ded. Therefore it is necessary to find out where from an ecological point of view are the most appro priate locations, for example in which no particularly sensitive benthic species or communities are living or in which a very quick recolonisation can be expected. Concerning the dyke reinforcement on the west side of the Jadebusen (sand requirement about 1.300.000 m*), the NLO - FSK has investigated the benthic fauna of several potential areas for sand removals in 1992 and 1994. On the basis of this research a removal from the eulitoral zone and from two sublitoral, more valuable locations was excluded. But there could be found two relatively appro priate locations in the sublitoral zone which showed no occurence of endangered species and which can be expected to get refilled and recolonized comparable to the status quo over a short period of approximately 6 years. 4 recently reaped saltmarsh F ig ...L Morphological structure of saltmarshes and a former clay pit on the east side of Jadebusen (Infra-red aerial picture) sea former clay pit dyke Fifl-2: Fjfl.,3: Detail of saltmarsh vegetation Typical vegetation of a former clay pit (east side of Jadebusen) (east side of Jadebusen) with Limonium vulgare with Puccinellia maritima, and Artemisia maritima Atriplex portulacoides and Aster tripolium WSNL 1991-1 ECOSYSTEM RESEARCH IN THE WADDEN SEA 7 Ecosystem Research in the Wadden Sea Peter K/tauer, Federal Environmental Agency, Berlin In 1978, the Federal Environmental Agency framework of the MAB-6 project "human (Umwellbundcsamt) commissioned a feasibili impacts on ecosystems in high mountain ty study on behalf of the Federal Ministry for regions". The project’s monitoring and data the Environment concerning the establishment compilation phase has meanwhile been com of applied ecosystem research. In this study, pleted, the assessment and data evaluation' the deficits existing at that time in ecological phase has been in progress since the begin research were described as follows: ning of 1989. - Not even for the most important ecosys tems functional relationships and control Since 1985 the Federal Environmental mechanisms have been investigated. Agency, on behalf of the Federal Minister for - The pollution load in and the load capacity the Environment, Nature Conservation and of living systems has not been sufficiently Nuclear Safety, has endeavoured to apply this clarified. approach to a second area to be designated as - Comprehensive ecological information is main research area. The Wadden Sea has available only for parts of the Federal been chosen not only because of the current ' Republic. situation. Due to this ecosystem’s sensitivity - Long-term ecological monitoring is not' and the acute dangers it faces, also its selec practiced. tion as the second ecosystem research project did not follow the principle of afeal represen- This analysis of deficits prompted the tatiyity, but took place under the aspect of its Federal Government to . establish a long-term meriting particular protection. ecosystem research program, with the objec tive of clearing up the functions, structures Also starting in 198S, Wadden Sea Nation and processes of the most important and al Parks and the corresponding administrative representative ecosystems in the Federal Re units bad been created in the Federal States public of Germany. - Schleswig-Holstein and Lower Saxony. The Federal Environmental Agency subsequently The approach pursued in this ecosystem entered into a cooperation with the National research program was confirmed by the Fed Park administrations in TOnning and Wil- eral Government in its "Guidelines on Antici helmshaven with the aim to establish the patory Environmental Protection", of 1986, second main research area. which called for the "building up of a net work of representative permanent monitoring The most important results of this coopera- areas (= main research areas) to record . tion are the two feasibility studies: changes in the most important ecosystems with the long-term aim of obtaining reliable - Christoph Leuschnen "Wadden Sea ecosys findings regarding the effects of material and tem research • development of the concept structural burdens". and organization of the overall pro- ject(sub-project Schleswig-Holstein)", and Following comprehensive preliminary work, the first main research area was estab - Thomas Hopnen "Conception of the eco- lished in 1981 in Berchtesgaden within the ‘ system research programme for the Wad- 8 ECOSYSTEM RESEARCH IN THE WADDEN SEA WSNL 1991-1 den Sea of Lower Saxony (sub-project 2. To generate the knowledge early enough Lower Saxony)", which were jointly pre that is necessary to solve or alleviate pared and published by (he two National environmental problems currently encoun Park administrations and the Federal Envi tered in the Wadden Sea. ronmental Agency. The two studies set the following goals for 3. To develop evaluation criteria and to pro the main phase of the Wadden Sea ecosystem vide a set of instruments to fulfill the research programme which is starting now: long-term tasks associated with the pro tection and monitoring of the Wadden 1. To obtain a basic understanding of the Sea. functioning of the system nature/man in the Wadden Sea, particularly for the pur Thereby the Federal Environmental Agency pose of solving future environmental will cot tribute to the extensive tasks to be problems, the possible consequences of tackled within the main phase of the Wadden which are unknown to us today. Sea ecosystem research programme. Umweltbundesamt Bismarckplatz 1 D-1000 Berlin 33 Applied Ecosystem Research Aim: analysis of natural processes and human impacts, development of monitoring strategies and ecological targets, scientific background for the further development of the. national park concept 19 research projects a. eutrophication - phytoplankton development - effects of Phaeocystis - blooms on blue mussels - black spots (pysical, biochemical, microbial changes, reaction of meio-and macrobenthos) b. musselbeds - structure and functions of natural mussel beds, seed, culture lots - effects of mussel fisheries - effects of bird predation c. monitoring and ecological targets _ - strategies for benthic communities, fish(es) - accumulation of pollutants in the food web - development of ecological targets d. fisheries - shrimp fishery as a food source of sea birds - socio-economical .development of the fisheries in the NLP of Lower Saxony e. interpretation of aerial photography with a GIS f. numerical modelling of ecological systems g. steering board (organization, operation, synthesis) WSNL 1993-3 Ecosystem Research 31 Additional Projects Approved for Research in the Wadden Sea Ecosystem Research in Lower Saxony Sabine Dittmann, National Park Administration Lower Saxonian Wadden Sea, Wilhelmshaven, FRG With the establishment of national parks for processes which require prime conservation the Wadden Sea in Germany, an ecosystem status. research scheme was inaugurated in the late 1980s. The scheme set up consists of two Over forty scientists of eight institutions corresponding parts carried out in Schleswig- participate in EL AW AT, covering ’’classic" Holstein and Lower Saxony, each composed disciplines, but applying latest methods. of two branches: one focussing on applied They deal with microbes, benthic and pelagic and the other on basic sciences. Projects are microalgae, meio- and macrobenthos as well well under way in Schleswig-Holstein, and as with birds of the Wadden Sea. Hydrogra since 1989 for the applied science part in phy, sedimentology, sediment chemistry and Lower Saxony. Here, after completing a meteorology are further subjects. Mathemati pilot phase for the basic branch in March cians analyze similarity of temporal and spa 1993, work can now continue on key ques tial patterns. The projects are linked by work tions of the ecology of this ecosystem. ing groups to assure an interdisciplinary ap proach. Work has commenced this autumn The Federal Ministry of Research and Tech and will continue till late 1996. Main study nology gave the go-ahead for eleven further areas are the tidal flats sheltered by the East projects under the theme of "EL AW AT" Frisian island of Spiekeroog. (Elastizitdt des Okosystems Wattenmeer - Resilience of the Wadden Sea ecosystem). The projects are financed with a total budget Nationalparkverwaltung of 7.3 Mill. DM over a three year duration. Niedersachsisches Wattenmeer Administration for EL AW AT is assigned to Virchowstr. I the Research Center Terramare, and scientific D - 26382 Wilhelmshaven coordination will be achieved by the project management located at the National Park Administration Office, both situated in Wilhelmshaven. To analyze the resilience of the Wadden Sea, the projects investigate temporal and spatial patterns on every hierarchy level of the eco system and record their variations following simulated disturbances. How can we judge whether a resilient response has occurred? What are the main ecological processes in action for the functioning of such a complex system as the Wadden Sea? Ultimately, this research will identify key components and 30 Impact Study Europipe WSNL 1993-3 Long-term Impact Study for the Europipe Development Project Manfred Vollmer, National Park Administration for the Lower Saxonian Wadden Sea, Wilhelmshaven, FRG The Norwegian company STATOIL plans position of the National Park Administration the construction of the gas pipeline "Euro are documented in the "Planfeststellungsbe- pipe" to deliver more natural gas from the schluB" of the Oberbergamt. Norwegian gasfields to Germany. This gas delivery is part of an international treaty The impact studies cover the following disci (’’Europipe agreement") between the King plines with a main emphasis on: dom of Norway and the Federal Republic of - hydrography: measurements of wave Germany. To land the pipeline at the German height, wave direction, tidal height, turbid coastline, the proposed route, fixed in the ity, current speed and current direction; "Landesplanerischen Feststellung" of the - morphology: monitoring of the tidal "Raumordnungsverfahren", follows the tidal channels in the Accumer Ee; inlet and the tidal channel between the - sedimentology: sediment composition and islands of Baltrum and Langeoog and contin distribution, measurements of sedimenta ues through the Accuxnersieler Balje and tion and erosion processes, investigations beneath the tidal flats of the "Domumer of suspended matter and on bedfonn devel Nacken". This subsurface crossing of the opment; mudflats requires a tunnel of 2.6 km length, - biology, this part is divided into the three where the pipeline will be laid in. following compartments: a. fish and decapode crabs: species rich - Extensive sediment dredging has to be done ness, population density, population for laying the pipeline in the tidal channels . dynamic and recruitment pattern, and To provide access fpr the laybarge to the studies on the black spot disease of Accumersieler Balje, a temporary channel brown shrimps; must be dredged through the sand bar separat b. benthos: diversity of habitats, studies ing the Accinner Ee tidal inlet from the sea. on seasonal dynamics of selected spe This and the fact that the pipeline has to be cies, monitoring of macrofauna in permanently covered with sediments require subtidal creeks, a survey of the threat the dredging work. The direct effects of the ened species and investigations on construction cover an area of 80 ha, the indi juvenile flatfish; rect effects will cause disturbances to the c. birds: monitoring of breeding birds and Wadden Sea behind the islands of Baltrum breeding success (number of young and Langeoog. To document effects of the fledged per pair), monitoring of migra "Europipe-landfall" on the ecology of the tory birds and time spacial pattern of area, extensive scientific investigations are selected species. necessary. The long-term impact studies Results from the impact studies will be com began in early 1993 and will continue for piled over six-months terms and published several years until an ecological evaluation annually. of the impact is possible. The studies are carried out by several research institutes and Nation alparkverwaltung are coordinated by the National Park Adminis Niedersachsisches Wattenmeer tration in Wilhelmshaven. The necessity for Virchowstr. 1 the environmental investigations and the D - 26382‘Wilhelmshaven Wadden Sea - cooperation area and present trilateral areas of conservation